阅读说明：本技术 一种用于复合材料修理后超声检测的试块 (Test block for ultrasonic detection after composite material repair ) 是由 刘松平 刘菲菲 杨玉森 张连旺 于 2020-12-17 设计创作，主要内容包括：本发明是一种用于复合材料修理后超声检测的试块,该试块由母片(1)和补片(2)组成,在母片(1)的中心处加工有一个圆锥形盲孔或圆锥形通孔,在该圆锥形盲孔或圆锥形通孔内设置与其形状、体积相匹配的补片(2),在补片(2)内设置分层缺陷,在补片(2)与母片(1)的圆锥形盲孔或圆锥形通孔的贴合面(3)上设置脱粘缺陷。该试块考虑了复合材料损伤修理的工艺特点、损伤区的几何特征,以及由此带来超声检测信号的变化对修理区缺陷的判别影响,更能反映复合材料损伤特点,结合损伤修理区超声检测的特点,给出的评价方法等更加适合复合材料修理区的超声检测与缺陷评定,从而更有利于提高修理检测的可靠性和修理缺陷评定的准确性。(The invention relates to a test block for ultrasonic detection after repair of a composite material, which consists of a master piece (1) and a patch (2), wherein a conical blind hole or a conical through hole is processed at the center of the master piece (1), the patch (2) matched with the conical blind hole or the conical through hole in shape and volume is arranged in the conical blind hole or the conical through hole, a layering defect is arranged in the patch (2), and a debonding defect is arranged on a bonding surface (3) of the patch (2) and the conical blind hole or the conical through hole of the master piece (1). The test block considers the process characteristics of composite material damage repair, the geometric characteristics of a damaged area and the discrimination influence of the change of ultrasonic detection signals on the defects of the repaired area, can better reflect the damage characteristics of the composite material, combines the characteristics of ultrasonic detection of the damaged repaired area, provides an evaluation method and the like which are more suitable for ultrasonic detection and defect evaluation of the composite material repaired area, and is more beneficial to improving the reliability of repair detection and the accuracy of repair defect evaluation.)

1. A test block for post-repair ultrasonic testing of composite materials, comprising: the test block is composed of a master piece (1) and a patch (2), the master piece (1) is the same as a composite material of a repaired part, the patch (2) is the same as the composite material for repair, a conical blind hole or a conical through hole is processed at the center of the master piece (1), the patch (2) matched with the shape and the volume of the conical blind hole or the conical through hole is arranged in the conical blind hole or the conical through hole, a layering defect is arranged in the patch (2), and a debonding defect is arranged on a bonding surface (3) of the conical blind hole or the conical through hole of the patch (2) and the master piece (1).

2. The test block for post-repair ultrasonic testing of composite materials of claim 1, wherein: the parent sheet (1) is the same as the composite material of the repaired part, which means that the material, the layering and the curing process of the parent sheet (1) are consistent with the composite material of the repaired part.

3. The test block for post-repair ultrasonic testing of composite materials of claim 1, wherein: the same of the patch (2) and the repair composite material means that the material, the laying and the curing process of the patch (2) are consistent with those of the repair composite material, and the fiber direction of the patch (2) and the fiber direction of the master piece (1)In parallel。

4. The test block for post-repair ultrasonic testing of composite materials of claim 1, wherein: the thickness H of the patch (2) and the included angle alpha between the side wall and the bottom of the conical blind hole or the conical through hole satisfy the following relational expression:

in the formula: d is the diameter of the large-diameter end of the conical blind hole or the conical through hole.

5. The test block for post-repair ultrasonic testing of composite materials of claim 1, wherein: the master slice (1) is rectangular in shape, the length of the master slice is L, the width of the master slice is W, and the length and the width satisfy the following relational expression:

and L is (1.0-1.5) multiplied by W formula 2.

6. The test block for post-repair ultrasonic testing of composite materials of claim 1, wherein: the large-diameter end of the conical blind hole is an opening end.

7. The test block for post-repair ultrasonic testing of composite materials of claim 1, wherein: the distance L between the edge of the opening end of the conical blind hole or the conical through hole and the edge of the master slice (1)₁The following relation is satisfied:

L₁(1.0-2.0) D formula 3

In the formula: d is the diameter of the large-diameter end of the conical blind hole or the conical through hole.

8. The test block for post-repair ultrasonic testing of composite materials of claim 5, wherein: the length L of the master slice (1) satisfies the following relational expression:

L＝2L₁+ D formula 4

In the formula: l is₁The distance between the edge of the opening end of the conical blind hole or the conical through hole and the edge of the master slice (1) is D, and the diameter of the large-diameter end of the conical blind hole or the conical through hole is D.

9. The test block for post-repair ultrasonic testing of composite materials of claim 1, wherein: and according to repair acceptance conditions, the layering defects are a plurality of layering defects with different thicknesses and different areas.

10. The test block for post-repair ultrasonic testing of composite materials of claim 1, wherein: and determining the debonding defects to be a plurality of debonding defects with different thicknesses and different areas according to repair acceptance conditions.

Technical Field

The invention relates to a test block for ultrasonic detection after repair of a composite material, and belongs to the technical field of measurement and testing.

Background

With the widespread use of composite materials in the fields of aviation, construction, transportation, and the like, various structures based on composite materials have gained very important service applications in many engineering fields. In a service environment, the composite material structure may be damaged due to the action of stress and the like. In order to ensure the original expected load-bearing capacity and function of the composite material structure, the damaged composite material structure needs to be repaired timely and effectively. The quality of repair of the damaged area directly affects the degree of recovery of the composite material's structural performance and function. Therefore, in engineering, 100% nondestructive testing is generally required for the repair quality of the damaged area of the composite material structure. The detection method adopted at present is to utilize a contrast test block containing known damage to acquire a detection signal and detection parameter setting for judging a damage threshold value, and then carry out ultrasonic detection on a damaged repair area of the composite material based on the set detection signal threshold value and detection parameter setting. Therefore, the rationality of the design of the reference block and its defect/damage setting is very important. The main defects of the current contrast test block design and evaluation method for ultrasonic detection of composite material damage repair are as follows: (1) only the material, process and structure characteristics of the composite material in the manufacturing stage are considered, and the damage repair characteristics of the composite material are not considered; (2) the defect setting does not reflect the damage characteristics of the composite material; (3) the corresponding evaluation method is not given in combination with the characteristics of ultrasonic detection of the damaged repair area.

Disclosure of Invention

The present invention is designed to overcome the defects in the prior art and provides a test block for ultrasonic detection after composite material repair, which aims to make ultrasonic detection of a composite material repair area more accurate and form an evaluation standard for defects.

The purpose of the invention is realized by the following technical scheme:

the technical scheme of the invention is based on ultrasonic reflection characteristics and geometric characteristics of a damaged repair area, and provides a test block for ultrasonic detection of composite material repair, wherein the test block is designed by taking the process characteristics of composite material damage repair, the geometric characteristics of a damaged area and the influence of the change of ultrasonic detection signals on the defects of the repair area into consideration, and the specific contents are as follows:

the test block for ultrasonic detection after composite material repair comprises a master 1 and a patch 2, wherein the master 1 is the same as the composite material of a repaired part, the patch 2 is the same as the composite material for repair, a conical blind hole or a conical through hole is processed at the center of the master 1, the patch 2 matched with the shape and the volume of the conical blind hole or the conical through hole is arranged in the conical blind hole or the conical through hole, the master 1 and the patch 2 are spliced by adopting the splicing process the same as damage repair, a layering defect is arranged in the patch 2, and a debonding defect is arranged on a splicing surface 3 of the conical blind hole or the conical through hole of the patch 2 and the master 1.

In one implementation, the parent sheet 1 is the same as the composite material of the part being repaired, meaning that the material, layup and curing process of the parent sheet 1 is consistent with the composite material of the part being repaired.

In one implementation, the patch 2 is the same as the repair composite material, meaning that the material, layup and curing process of the patch 2 is the same as the repair composite material, and the fiber direction of the patch 2 is the same as the fiber direction of the master 1In parallel。

In one implementation, the thickness H of the patch 2 and the angle α between the side wall and the bottom of the conical blind hole or conical through hole satisfy the following relation:

in the formula: d is the diameter of the large-diameter end of the conical blind hole or the conical through hole.

In one embodiment, the master 1 is rectangular in shape, having a length L and a width W, both satisfying the following relationship:

and L is (1.0-1.5) multiplied by W formula 2.

In one implementation, the large diameter end of the conical blind hole is an open end.

In one implementation, the edge of the open end of the conical blind hole or the conical through hole is spaced from the nutDistance L of sheet 1 edge₁The following relation is satisfied:

L₁(1.0-2.0) D formula 3

In the formula: d is the diameter of the large-diameter end of the conical blind hole or the conical through hole.

In one implementation, the length L of the master 1 satisfies the following relation:

L＝2L₁+ D formula 4

In the formula: l is₁The distance from the edge of the opening end of the conical blind hole or the conical through hole to the edge of the master slice 1, and D is the diameter of the large-diameter end of the conical blind hole or the conical through hole.

In one implementation, the delamination defect is a number of delamination defects at different thicknesses, different area sizes, depending on repair acceptance conditions.

In one implementation, the debonding defect is a plurality of debonding defects of different thicknesses and different area sizes as determined by repair acceptance conditions.

When the test block is evaluated, the test block is detected by an ultrasonic reflection method, and the ultrasonic attenuation difference delta in the non-preset defect area of the master film 1 and the patch 2₁<When the power is 6dB, the evaluation is qualified; the ultrasonic attenuation difference delta between the bonding surface 3 of the master slice 1 and the patch 2 without the debonding area and the debonding defect position₂>When the power is 6dB, the evaluation is qualified; difference in ultrasonic attenuation Δ between non-delaminated area of patch 2 and delaminated defect location within patch 2₃>And when the power is 6dB, the evaluation is qualified. The evaluation adopts a high-resolution ultrasonic A, B, C scanning method, and the frequency selection range of ultrasonic scanning is 2MHz-10 MHz.

The test block is provided based on ultrasonic reflection characteristics and geometric characteristics of a damaged repair area and an ultrasonic reflection method detection and defect identification principle, the test block can accurately represent the defects of the repair area through changes of ultrasonic detection signals, further accurately reflect the damage characteristics of the composite material, and an evaluation method and the like provided by combining the characteristics of ultrasonic detection of the damaged repair area is more suitable for ultrasonic detection and defect evaluation of the composite material repair area, so that the reliability of repair detection is improved.

Drawings

FIG. 1 is a schematic diagram of the shape and structure of the test block of the present invention

Detailed Description

The technical scheme of the invention is further detailed in the following by combining the drawings and the embodiment:

referring to fig. 1, the carbon fiber composite material laminated test block with three thicknesses of 4mm, 8mm and 10mm is selected as the master piece (1) of the test block in the embodiment, wherein the length L and the width W of the master piece (1) with the thickness of 4mm are 900mm respectively, the length L and the width W of the master piece (1) with the thickness of 8mm are 800mm respectively, the length L and the width W of the master piece (1) with the thickness of 10mm are 750mm respectively, the master piece (1) is the same as the composite material of the part to be repaired, the patch (2) is the same as the composite material for repairing, and the fiber direction of the patch (2) is the same as the fiber direction of the master piece (1)In parallel with each other, the two groups of the material,a conical through hole is processed in the center of the master piece (1), a patch (2) matched with the conical through hole in shape and volume is arranged in the conical through hole, a layering defect is arranged in the patch (2), and a debonding defect is arranged on a binding surface (3) of the patch (2) and the conical through hole of the master piece (1). The carbon fiber composite material with the thickness of 4mm is 300mm, D is 100mm, the carbon fiber composite material with the thickness of 8mm is 200mm, D is 50mm, the carbon fiber composite material with the thickness of 10mm is 150mm, D is 30mm, the delamination defects of the test blocks with the thicknesses of 4mm, 8mm and 10mm are respectively positioned on the surface of the near patch (2), the middle depth of the patch (2) and the thickness position of the bottom surface of the near patch (2), and the diameter phi of the delamination defect at each thickness position₁、Φ₂、Φ₃、Φ₄The debonding defects of test blocks with the thicknesses of 6mm, 9mm, 12mm, 19mm,4mm, 8mm and 10mm are respectively positioned at the positions close to the surface of the patch (2), the middle depth of the patch (2) and the thickness of the bottom surface of the patch (2), and the diameter phi of the debonding defect at each thickness position₁、φ₂、φ₃、φ₄Respectively 6mm, 9mm, 13mm and 20mm, preparing three test blocks with different thicknesses for ultrasonic detection for repair, adopting CUS-21J ultrasonic detection produced by Zhonghang composite material Limited liability company, selecting frequencies of 2, 5 and 10MHz, and respectively performing ultrasonic A, B, C scanning on the test blocks prepared by designThe detection and evaluation result shows that the both can meet the delta₁<3dB、Δ₂>6dB，Δ₃>6dB, and a better actual detection effect is obtained.